Batteries are used in a wide variety of electronic and electrical devices. It is desirable to be able to estimate the internal state-of-charge of a battery cell, the resistance of a battery cell, and the residual available energy of a battery cell.
Many algorithms have been proposed for the purpose of battery cell state-of-charge estimation. Very often, there is a tradeoff between the complexity of the algorithm and the accuracy of the results that it produces. Very accurate results tend to be produced only by very complex algorithms, which in turn require significant processor resources to execute. Accurate results at a lower complexity are desirable.
Furthermore, certain applications demand higher accuracy at different operational points. It may not be necessary for very high estimation accuracy when the battery cell is in the mid-range of its capacity. It may be more important to have high estimation accuracy when the battery cell is nearly fully charged or when it is nearly fully discharged.
Accordingly, the inventor herein has recognized a need for an improved method for more efficiently determining an estimated battery cell state-of-charge when the battery cell is either nearly fully charged or nearly fully discharged. Furthermore, the inventor has recognized a need for an associated battery cell resistance estimate and a battery cell available energy estimate.